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My way of finding lengths between 2 pts(complex numbers),what's wrong?

  • Thread starter inv
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  • #1
inv
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[Solved]Length formula to find lengths between 2 pts(complex numbers),what's wrong?

Homework Statement


I've 3 pts U(2i),A(-√3 -i) & B(√3-i),all complex numbers.A question asks me to prove UAB is equilateral.


Homework Equations


|AB|=√{(b-a)^2} for finding lengths.


The Attempt at a Solution


So I try to find two of it's lengths AB and UA.
|AB|=√(b-a)^2
=√{4(3)}
=√12
|UA|=√{a-u}^2
=√(-√3-3i)^2
=√(3-9)
=√-6
The two lengths not same,what's wrong here?
 
Last edited:

Answers and Replies

  • #2
Hootenanny
Staff Emeritus
Science Advisor
Gold Member
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In general we can find the modulus of a complex number thus;

[tex]|z| = \sqrt{z\bar{z}}[/tex]

Also note that [itex]\left(-\sqrt{3}-3i\right)^2 \neq (3-9)[/itex] as you have in your solution for |UA|
 
  • #3
inv
45
0
Problem solved and thx indeed*
 

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